2003 -- Alderslade - Lowhowia koosi

A new genus and species of soft coral (Octocorallia: Alcyonacea:Alcyoniidae) from Lord Howe Island, Australia

P. Alderslade

Alderslade, P. A new genus and species of soft coral (Octocorallia: Alcyonacea: Alcyoniidae) fromLord Howe Island, Australia.Zool. Verh. Leiden 345, 31.x.2003: 19-29, figs 1-7.— ISSN 0024-1652/ISBN 90-73239-89-3.Philip Alderslade, Museum and Art Gallery of the Northern Territory, P.O. Box 4646, Darwin, NT,0801, Australia.

Key words: Coelenterata; Cnidaria; Octocorallia; Alcyoniidae; Alcyonacea; Lohowia; new species; newgenus; Australia; Lord Howe Island.Lohowia koosi, a new species and new genus in the family Alcyoniidae, is described from Lord HoweIsland, Australia. The new taxon has dimorphic polyps and a similar morphology to some of the flat,lobe-less nominal species of Lobophytum. The new taxon is clearly distinguished, however, by thepossession of large, heavily armed autozooids, polypary surface sclerites in the form of large spindlesthat protrude through the surface, extremely large interior sclerites and base surface sclerites in theform of rods, spindles and ovals.

Introduction

Lord Howe Island, a high island, is the erosional remnant of a 6.9 million-year oldshield volcano. The Island is about 10 km long and about 1.5 km wide and is situatedin the northern region of the Tasman Sea on the western margin of the Lord HoweRise. This rise is approximately 320 km wide and 1575 km long and runs in a more orless northwesterly direction from off the South Island of New Zealand. A chain ofseamounts extends for about 1000 km northwards from Lord Howe Island far into thecoral sea (McDougall et al., 1981).

Lord Howe is about 600 km off the coast of northern New South Wales, and isadministratively part of that state. The island region, which is on the UNESCO WorldHeritage List and incorporates a Marine Park, is surrounded by the southernmostcoral reefs in the world, lying beyond 31ºS, where the ocean currents have permittedthe development of a unique mix of both temperate and tropical faunas. Ponder et al.stated in a 2002 report; “The marine biota of Lord Howe is known to have a numberof endemic species in shallow water and on the shelf, but the deeper water fauna isunknown. There has never been a full-scale survey of the marine invertebrates ofLord Howe Island, although there is some information (reviewed by Pollard andBurchmore 1985). By far the best known group is the corals (Veron and Done 1979;Harriott et al. 1993; Harriott et al. 1995; Pichon 1995), . . . Harriott et al. (1993) under-took a baseline study to determine the status and structure of the “marine benthic(coral) communities” and compared their findings with published records .. . A totalof 59 coral species were recorded during their study (including 19 not previouslyrecorded from Lord Howe), bringing the total to 83 species of corals known from theisland (c.f. 356 from the GBR), a very high diversity considering the latitude and isola-tion of the island (Harriott et al. 1993; Harriott et al. 1995). Other groups of marineinvertebrates have not been synoptically reviewed and are rather poorly known. For

Alderslade. A new genus and species of soft coral from Australia. Zool. Verh. Leiden 345 (2003)20

example, there are five described species of ascidians known from the island but per-haps 50 occur there (P. Mather pers. comm.). A number of endemic marine molluscsare known (Allan and Iredale 1939; Iredale 1940; Ponder 1981).”

The octocorals of the region have never been studied in any detail. The new taxondescribed below comes from a collection made by natural science author and under-water photographer Neville Coleman. Mr Coleman has made several collections onthe Island during his research for a recently published field guide (Coleman, 2002).The material, yet to be identified beyond generic level, is stored in the Museum andArt Gallery of the Northern Territory (MAGNT) and includes species of; Tubipora, Sin-ularia, Sarcophyton, Lobophytum, Cladiella, Rhytisma, Eleutherobia, Lemnalia, Dendroneph-thya, Xenia, Sympodium, Briareum, Erythropodium, Mopsella, and Acabaria.

The abbreviation NTM refers to Museum and Art Gallery of the Northern Territo-ry, Darwin.

Systematic part

Family Alcyoniidae LamourouxLohowia gen. nov.

Type species.— Lohowia koosi spec. nov. by original designation.Diagnosis.— Colony low, massive and encrusting. Polypary without lobes, and

slightly dished. Polyps dimorphic. Autozooids relatively large, retractile, and heavilyarmed with spindles in a collaret and points arrangement. Polyp tentacles with rowsof numerous fattened rods. Siphonozooids with a few short rods or double cones thatcommonly have a waist and tuberculate ends. Surface of the polypary contains athick, dense layer of short to long, narrow spindles that are arranged perpendicular tothe surface. The tips of many of these spindles protrude through the surface and forma row around the siphonozooids and autozooids. The surface of the base contains athin layer of short rods, tuberculate spindles and ovals arranged in all directions. Thecolonial interior contains short to very large (up to 4 mm), longitudinally arrangedspindles with spiny tubercles. Zooxanthellate.

Etymology.— The name is derived from the type location, Lord Howe Island, andis feminine.

Remarks.— In several respects, Lohowia gen. nov. resembles the genus Lobophytum(Marenzeller, 1886). The latter is dimorphic, low, massive and encrusting, and includesseveral nominal species with a more or less lobe-less polypary (e.g. L. patulum Tixier-Durivault, 1956, L. variatum Tixier-Durivault, 1957 and L. depressum Tixier-Durivault,1966, see colony pictures in Verseveldt, 1983). In Lobophytum, however, the autozooidsare relatively small and are only lightly armed with small rods, the surface of poly-pary and the base contain a thin layer of small clubs, the sclerites in the polypary sur-face do not protrude, and the interior of the colony contains small spindles or ovals,rarely longer than 0.5 mm, which have large tubercles generally arranged in a smallnumber of girdles.

Given the high latitude of Lord Howe Island (31ºS), it is worth also noting the sim-ilarities between the new taxon and Skamnarium Alderslade, 2000 which is onlyknown from 32ºS off the west coast of Australia. Skamnarium also forms colonies with

21Alderslade. A new genus and species of soft coral from Australia. Zool. Verh. Leiden 345 (2003)

Fig. 1. Lohowia koosi gen. nov., spec. nov.; aspects of the holotype. Life size � 2.


Fig. 2. Lohowia koosi gen. nov., spec. nov.; holotype; A, polypary surface; B, broken face of colony; C,polypary surface. Abbreviations: au = autozooid; au ap = autozooid aperture; po sur = polypary sur-face; sc ti = sclerite tips; si = siphonozooid.

A

CB


a flat or dished polyparium and the coenenchyme contains large tuberculate rods upto 4 mm in length. However, the polyps are monomorphic and unarmed, and thereare no separate surface layers of sclerites in any region of the colony.

Lohowia koosi spec. nov.(figs 1-7)

Material.— Holotype NTM C14232, No Name Rock, Lord Howe Island, 31º33’S, 159º05’E, depth 13 m,Neville Coleman, 17.vii.2002.

Description of holotype.— The holotype (fig. 1) is a portion torn from the originalcolony. It is 66 mm long and 20-35 mm across. The greatest thickness is 20 mm in aregion where the base is 15 mm tall. The polypary has a dished surface and there areno lobes or ridges. The cross section exposed by the sampling (fig. 2B) clearly showsthe densely packed interior sclerites, the layer of smaller surface sclerites, and clustersof oocytes (0.14-0.44 mm in diameter) in the mid-to-lower regions of the gastric canalsof the autozooids.

The polyps are dimorphic, and the siphonozooids and the apertures left by theretracted autozooids are clearly visible. On the curved rim of the polypary there areabout 0-3 siphonozooids between two autozooids. In the central region near the cutedge the number is 1-6 between two autozooids. Most siphonozooids are completelydeflated (fig. 2A), but in the central region of the sample, especially close to the tornedge, many remain relatively well inflated and appear as low domes about 0.4 mmacross (fig. 2C).

The apertures left by retracted autozooids, together with their octate surround (fig.2A), are up to about 1.25 mm in diameter. Several autozooids in the vicinity of the tornedge are exert (fig. 2B, C) and these are up to 1.5 mm tall and 0.9 mm in diameter.

Autozooid polyps are heavily armoured with sclerites in a collaret and points

Fig. 3. Lohowia koosi gen. nov., spec. nov.; holotype; examples of the arrangements of polyp sclerites.


Fig. 4. Lohowia koosi gen. nov., spec. nov.; holotype; A, polyp head sclerites; B, tentacular sclerites; C,siphonozooid sclerites; D, polypary surface sclerites.

A

B

C

D


arrangement (fig. 3). The sclerites are spindles or rods, mostly slightly curved, whichare ornamented with cone-shaped tubercles (fig. 4A). The sclerites are about 0.16-0.5mm in length and their number and arrangement is very varied. The tentacles containflattened rods (fig. 4B) about 0.05-0.19 mm long. They would probably align in a singlerow in an expanded tentacle rachis, but in the holotype’s contracted tentacles they arearranged both obliquely and transversally.

The siphonozooids also contain a few sclerites. They are small rod-like forms, 0.04-0.06 mm long, that often have the simple tubercles clustered on the enlarged ends (fig.4C). They can be seen in a number of the inflated siphonozooids arranged like smallspokes around the centre point. There is commonly 1-2 in each octant.

Fig. 5. Lohowia koosi gen. nov., spec. nov.; holotype; basal surface sclerites.


Fig. 6. Lohowia koosi gen. nov., spec. nov.; holotype; A, sclerites of interior of polypary with details oftubercles; B, sclerites of interior of base with detail of tubercles.

A

B


Fig. 7. Lohowia koosi gen. nov., spec. nov. A, live colony from which the holotype was removed; B, por-tion of a group of fission clones, about 1.5 m cross, suspected of being this species. Photographs byNeville Coleman.

A

B


The surface layer of the polypary contains spindles about 0.6-1.5 mm long that haveone, smooth, roundly pointed end (fig. 4D). The remainder of the sclerite is orna-mented with short, transverse rows of spiny tubercles like those that occur on theinterior sclerites (see fig. 6). The spindles are arranged perpendicular to the surfaceand their smooth distal end protrudes through the coenenchyme forming circlesaround the polyps (fig. 2A).

In the surface layer of the base, more or less nestled between the outermost interiorsclerites below a soft “dermal” layer, there are numerous small sclerites. They arerods, spindles and ovals that are commonly 0.16-0.77 mm in length (fig. 5). Most areornamented with large, complex tubercles.

The interior of the holotype contains large, densely packed, spindles up to about4 mm in length. They are ornamented with spiny tubercles arranged in short trans-verse rows. The spindles in the basal region are the largest and have the largesttubercles (fig. 6B). Those in the polypary are shorter and narrower and have smallertubercles (fig. 6A).

Colour.— The holotype is violet-brown; paler in the exposed part of the colonyinterior. This colour is clearly a stain derived from another organism, probably asponge, kept in the same container during preservation, and does not penetratedeeply into the coenenchyme. The colony from which the holotype sample wasremoved can be seen in fig. 7A. It has the general appearance of greenish grey polypsover a brownish grey surface that is seen in many species of such alcyoniid genera asLobophytum, Sarcophyton and Sinularia. The colonies pictured in Fig. 7B, photographedat Roach Island, which is just over one kilometre to the NE of Lord Howe Island, arethought by Neville Coleman to also represent the new species. With the polypsretracted the fission clones have a definite bluish hue.

Etymology.— Dr Jacobus Cornelis den Hartog was known to friends and col-leagues as Koos, and the new species is named in his honour. I can still recall my firstmeeting with Koos more than two decades ago when visiting the Leiden Museum foroctocoral research. Unable to secure reasonable priced accommodation for my family,Koos and his lovely wife Ruth unselfishly invited us to lodge at their house. Weremained in periodic contact from that time until his passing.

Acknowledgements

I offer my sincere thanks to Neville Coleman for donating his collected material tothe MAGNT and for allowing the publication of his underwater photographs. Mythanks also to Leen van Ofwegen for his invitation to contribute to this dedicatoryvolume and for his comments on my draft manuscript.

References

Alderslade, P., 2000. Four new genera of soft corals (Coelenterata: Octocorallia), with notes on the clas-sification of some established taxa.— Zool. Med. Leiden 74(16): 237-249.

Allan, J. & T. Iredale, 1939. A review of the relationships of the Mollusca of Lord Howe Island.— Reportof the Australian and New Zealand Association for the Advancement of Science 113. Canberra.

Coleman, N., 2002. Lord Howe Island Marine Park, Sea shore … to … Sea Floor. Neville Coleman’sUnderwater Geographic Pty. Ltd. Brisbane.


Harriott, V.J., P.L. Harrison & S.A. Banks, 1993. The marine benthic communities of Lord HoweIsland. Report for the Australian National Parks and Wildlife Service.— Northern Rivers, Centrefor Coastal Management, University of New England, 88 p.

Harriott, V.J., P.L. Harrison & S.A. Banks, 1995. The coral communities of Lord Howe Island.—Marine and Freshwater Research 46: 457-465.

Iredale, T., 1940. Marine molluscs from Lord Howe Island, Norfolk Island, Australia and New Guinea.—Australian Zoologist 9: 429-443.

Marenzeller, E. von, 1886. Ueber die Sarcophyton benannten Alcyoniiden.— Zool. Jahrb. (Syst.) 1: 341-368.McDougall, I., B.J.J. Embleton & D.B. Stone, 1981. Origin and evolution of Lord Howe Island, South-

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Pollard, D.A. & J.J. Burchmore, 1985. Lord Howe Island Regional Environmental Study: Marine envi-ronment with a proposal for an aquatic reserve.— Lord Howe Island Board, 59 p.

Ponder, W.F., 1981. Marine Mollusca. In: Recher, H.F & Ponder, W.F. (eds.), Lord Howe Island. Asummary of current and projected scientific and environmental activities.— Sydney, OccasionalReports of the Australian Museum 1: 10.

Ponder, W., P. Hutchins & R. Chapman, 2002. Overview of Australian Marine Invertebrates. A reportfor Environment Australia July 2002. Australian Museum, Sydney. <http://www.amonline.net.au/ invertebrates/marine_overview/index.html > (13 Feb. 2003).

Veron, J.E.N. & T.J. Done, 1979. Corals and coral communities of Lord Howe Island.— AustralianJournal of Marine and Freshwater Research 30: 203-236.

Tixier-Durivault, A., 1956. Les Alcyonaires du Muséum. 1. Famille des Alcyoniidae. 4. Genre Lobo-phytum.— Bull. Mus. nat. Hist. nat. Paris (2) 28 (6): 541-546.

Tixier-Durivault, A., 1957. Les Alcyonaires du Muséum. 1. Famille des Alcyoniidae. 4. Genre Lobo-phytum.— Bull. Mus. nat. Hist. nat. Paris (2) 29 (1): 106-111.

Tixier-Durivault, A., 1966. Octocoralliaires de Madagascar et des îles avoisinantes.— Faune de Madag-ascar 21: 1-456.

Verseveldt, J., 1983. A revision of the genus Lobophytum von Marenzeller (Octocorallia, Alcyonacea).—Zool. Verh. Leiden 200: 1-103.

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2003 -- Alderslade - Lowhowia koosi